All I need is to check, using python, if a string is a valid math expression or not.

For simplicity let's say I just need + - * / operators (+ - as unary too) with numbers and nested parenthesis. I add also simple variable names for completeness.

So I can test this way:

test("-3 * (2 + 1)") #valid
test("-3 * ")        #NOT valid

test("v1 + v2")      #valid
test("v2 - 2v")      #NOT valid ("2v" not a valid variable name)

I tried pyparsing but just trying the example: "simple algebraic expression parser, that performs +,-,*,/ and ^ arithmetic operations" I get passed invalid code and also trying to fix it I always get wrong syntaxes being parsed without raising Exceptions

just try:

>>>test('9', 9)
9 qwerty = 9.0 ['9'] => ['9']
>>>test('9 qwerty', 9)
9 qwerty = 9.0 ['9'] => ['9']

both test pass... o_O

Any advice?